What is the function of a headlight ballast?

[OJoshua]

The functions of a headlight ballast are: 1. It features a cold start current of less than 6.5A (common ballasts are 8.5A~9A or even higher): fast start-up speed, with a circuit designed to automatically adjust and supply current, commonly known as the secondary power supply function, making it compatible with HID bulbs from different manufacturers with varying tube voltages. 2. It has a wide voltage design performance: typically 7.5V~18V (common ballasts are 9V~16V), ensuring normal start-up under both low and high voltages. 3. During hot start or light switching, the start current is less than 5A: reducing the load on the car's power supply and the impact on other electrical devices due to frequent light changes; protecting the car's original wiring and its own protection system by minimizing instantaneous power load; fast start-up speed with low current, eliminating long start-up times due to reduced current and minimizing visual interference caused by light switching at night; low current start prevents bulb aging or light decay and reduces interference with other vehicle electronic devices.